Vehicle passenger seat airbag device

Abstract

A vehicle passenger seat airbag device includes: an airbag main body that is stored on a lower side of an instrument panel and that is partitioned by an upper partition member to a lower chamber that restrains lower limbs of an occupant and an upper chamber that restrains an upper body of the occupant; and a flow straightening cylinder that is provided so as to be passed through the upper partition member inside the airbag main body and that distributes gas ejected from an inflator to the lower chamber and the upper chamber. The flow straightening cylinder is provided such that a sectional shape of at least a region passing through the upper partition member is provided in a flat shape with its longitudinal direction in a vehicle width direction when the flow straightening cylinder expands and deploys due to ejection of the gas.

What is claimed is: 
     
       1. A vehicle passenger seat airbag device comprising:
 an airbag main body that is stored on a lower side of an instrument panel and configured to be located in front of an area from a knee to a shin of an occupant seated in a passenger seat of a vehicle, and that is partitioned by an upper partition member into a lower chamber configured to restrain a lower limb of the occupant and an upper chamber configured to restrain an upper body of the occupant; and 
 a flow straightening cylinder that is provided so as to be passed through the upper partition member inside the airbag main body and that distributes gas ejected from an inflator to the lower chamber and the upper chamber, wherein the flow straightening cylinder has a first length in a front-rear direction at a first central portion in a vehicle width direction in a region passing through the upper partition member, the first length is shorter than a portion other than the first central portion when the flow straightening cylinder expands and deploys due to ejection of the gas. 
 
     
     
       2. The vehicle passenger seat airbag device according to  claim 1 , wherein
 the lower chamber is partitioned into a first lower chamber and a second lower chamber by a lower partition member, and 
 the flow straightening cylinder is also provided so as to be passed through the lower partition member, and has a second length in the front-rear direction at a second central portion in the vehicle width direction in a region passing through the lower partition member, the second length is shorter than a portion other than the second central portion when the flow straightening cylinder expands and deploys due to ejection of the gas. 
 
     
     
       3. The vehicle passenger seat airbag device according to  claim 1 , further comprising a tether attached to the flow straightening cylinder that regulates the first length of the first central portion in the front-rear direction. 
     
     
       4. The vehicle passenger seat airbag device according to  claim 1 , wherein the flow straightening cylinder is provided so as to form a curved shape along an outer shape of a rear surface of the instrument panel when the flow straightening cylinder expands and deploys due to the ejection of the gas. 
     
     
       5. The vehicle passenger seat airbag device according to  claim 1 , wherein the airbag main body includes a first plane panel disposed on an instrument panel side and a second plane panel disposed on an occupant side, and a circumference along a vertical direction of the first plane panel is set to be shorter than a circumference along a vertical direction of the second plane panel. 
     
     
       6. The vehicle passenger seat airbag device according to  claim 1 , wherein an opening is provided in the upper partition member, and a gap is formed between a peripheral edge portion of the opening and an outer peripheral surface in the first central portion in at least the region passing through the upper partition member. 
     
     
       7. The vehicle passenger seat airbag device according to  claim 1 , further comprising a right tether and a left tether attached to the flow straightening cylinder that regulate the first length of the first central portion in the front-rear direction.